Cytotoxicity of various types of coated upconversion nanoparticles. Overview

Background and Objectives: The object of the study was the cytotoxicity of various types of coated upconversion nanoparticles. The aim is to overview the literature on the cytotoxicity of various types of upconversion nanoparticles without/with coating and to search for their maximum permissible concentration when applied to cell. Materials and Methods: The approach used has been the analysis of recent publications on the topic. Results: Upconversion nanoparticles are promising for fluorescence imaging and cancer therapy. Nanoparticles with additional shells or functionalized by surface coating with targeted or photoactive molecules are considered. The toxicological effect of nanoparticles on living organisms is of decisive importance when they are used in therapy or diagnostics. The "dark" cytotoxicity of particles is considered. The cytotoxicity of particles depends on the total number of nanoparticles that have penetrated into the cell. Conclusion: Based on the analysis of a large number of publications, it can be concluded that nanoparticles coated with silicon dioxide (SiO2) are characterized by the least cytotoxic effect, which opens up prospects for the use of this type of nanoparticles in medical practice.